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HARDWOOD RECORD 



ployed for the large "power switchboards" 

 which are a feature of certain plants. 



"When in doubt use oak" appears to be 

 the rule of cabinet-makers who turn out elec- 

 trical casings, as it is of cabinet-makers in 

 general. Oak is always a favored material, 

 and it is used solid in practically all cases. 

 For instance, telephones in birch or mahog- 

 any are much less common. In switchboards 

 the use of these woods is more frequent, 

 though here also oak is predominant, and the 

 finish of telephones and switchboards is Uke 

 that on the better grades of furniture. 



It is extremely seldom that special woods 

 are called for in telephone work, though an 

 occasional order comes for the mission oak 

 finish. The Kellogg Switchboard & Supply 

 Company recently supplied the Gadsden 

 hotel, newly erected at Bisbee, Ariz., with 

 switchboard and complete set of room tele- 

 phones in a special pattern to harmonize 

 with the general architectural scheme of the 

 building. There are occasional calls for 

 black walnut, and for ebonized and white 

 enamel finishes, the body-wood for the two 

 last-named generally being maple. The 

 qualities demanded in electrical cabinet ma- 

 terials are appearance, toughness and free- 

 dom from liability to warp. The thickness 

 of the wood in both telephones and switch- 

 boards is generally about % of an inch, 

 except in cornices, where in switchboards it 

 is sometimes 2 or 2% inches. 



Built-up construction is not employed in 

 the manufacture of these modern necessities, 

 1 am informed, excepting in the portion of 

 a switchboard that is called the key shelf. 

 This is the part roughly corresponding to the 

 keyboard in a piano — the horizontal ledge 

 containing the keys, and extending out 

 toward the operator at about the height of 

 a table. The plugs are just behind the 

 keys, on what a layman would call the self- 

 same table, but a hinged partition divides 

 them, and it is the front part that the adept 

 in switchboard construction calls the "key 

 shelf" proper. This is built up from five 

 layers of wood cross-banded so as to give 

 extra strength and prevent warping. The 

 built-up construction is necessary here on 

 account of the great weight of the electrical 

 apparatus that is attached to the top and 



the bottom of the shelf, which is hinged and 

 provided with a spring lock so that the 

 mechanism and wiring beneath can be readily 

 examined if desired. 



The rear part, containing the plugs, is 

 made of one soUd piece of wood covered 

 with sole leather to protect the cabinet work 

 from the impact of the plugs. The front 

 panel below the key shelf and the back panel 

 are made removable and are held in place by 

 spring catches. The bottom of the panel 

 is secured by a tongue fitted to a groove in 

 the cabinet, which method is believed to be 

 better than the use of dowel pins or other 

 devices. 



KEY SIIEI.K OF MODERN SWITCHBOARD. 



Above the key shelf is the iron "jack 

 frame, ' ' fastened into the face of the cab- 

 inet and containing various devices which 

 are known as ' ' drops, " " jacks, ' ' etc. Hard 

 rubber is the chief surface material employed 

 here when the jack frame is full, but the 

 possibility of great expansion is required in 

 most switchboards, so that a large space is 

 usually left blank, and this is filled in with 

 ebonized wood blanks. Fronts and backs of 

 switchboards are generally of the same wood 

 and finish; there is some slight use of wood 

 in the circuit mechanism, such as maple 

 bases for induction coils, etc. 



In telephones the prevailing types are the 

 wall and desk, the long telephones being 

 considered out of date. In the last-named 

 the part extending downwards to the floor 

 from the box containing the mechanism is 

 usually empty, and has no value except as 

 an alleged ornament. 



Telegraph poles, which form a tremendous 

 item in the increased demand for forest 

 products which electricity has created, are 

 of various woods, depending upon the flora 

 of the locality. The commonest choice for 

 pole stock is cedar, of several varieties. 

 Another much-used wood is cypress. Pine, 

 treated with a powerful preservative, is also 

 employed. The qualities demanded are 

 straightness, height and durability, all of 

 which are intensely characteristic of certain 

 American varieties of cedar and cypress. 

 Pine is lacking in durability, but it is 

 claimed that when carefully treated with 

 preservatives it will answer the purpose. 

 Cross-arms are usually of yellow pine, some- 

 times of Norway pine or Washington fir. 

 The red paint with which they are generally 

 covered is a preservative. Cedar and cypress 

 are best for poles because they are not liable 

 to rot in the ground. In cross-arms, how- 

 ever, no such quality is necessary, and there- 

 fore the question of cheapness pre- 

 vails. Security demands considerable height 

 in the telegraph pole. The measurement 

 from base to summit ranges from twenty-five 

 to forty feet, of which about five feet is in 

 the ground. Eailway tracks must be cleared 

 by twenty-five feet. 



From telephones and switchboards to 

 electro-medical apparatus is not a far cry, 

 and here again the cabinet-maker plays an 

 important part in their manufacture. One 

 would perhaps think that physicians would 

 be likely to make good customers for made- 

 to-order, hand-carved stock, but such is 

 not the case. The designs for large electro- 

 medical cabinets are usually handsome and 

 exhibit some high-grade machine carving, but 

 they are of conventional design, just as is 

 the case with the telephone and the switch- 

 board. Oak is again the favorite. In the 

 factory of the Mcintosh Battery & Optical 

 Company, the greater number of table and 

 wall plates, and vibrators of the type seen 



I'ANEL CONSTRUCTIO 



CROSS SECTION OF KEI SHELF. 



